(1) Technical Field
The present invention relates to an eyeglass lens processing apparatus for processing an eyeglass lens.
(2) Related Art
In an eyeglass lens processing apparatus, an eyeglass lens is held (chucked) by two lens chuck shafts and is rotated, while the peripheral edge of the lens is processed by a processing tool such as a grindstone so that the lens can have a shape substantially identical with a target lens shape (traced outline). To hold the lens, a cup serving as a fixing jig is mounted on and fixed to a front refractive surface of the lens through a double-sided adhesive tape, the cup with the lens fixed thereto is mounted on a cup receiver at a distal end of one of the two lens chuck shafts, and a lens holder at a distal end of the other lens chuck shaft is brought into contact with a rear refractive surface of the lens. Further, to hold a lens having a refractive surface easy to slip such as a lens on which a water repellant coating is enforced, a film-shaped adhesive sheet may be bonded onto the refractive surface of the lens and, after then, the cup is mounted on and fixed to the lens through a double-sided adhesive tape.
When processing the lens, the shape of the lens is measured (the edge position of the lens is detected) in accordance with the target lens shape. In this case, when the adhesive tape is bonded in such a manner that it is sticking out of the cup greatly, or when the adhesive sheet is bonded while creased, there is a possibility that an error can be included in the measuring result. And, when the lens is processed based on the processing data that have been obtained from the measuring results containing such error, defective processing can occur. Such defective processing can also occur similarly when some other foreign bodies stick to the refractive surface of the lens.